Guide for sharpening drill bits



Feb. 4, 1958 w. w. THUMANN GUIDE FOR SHARI'DENING DRILL BITS Fi led'March 5, 1956 INVENTOR WESLEY W. THUMANN W W United States Patent f GUIDE FOR SHARPENING DRILL BITS Wesley W. Thumann, Memphis, Tenn. Application March 5, 1956, Serial No. 569,389

7 Claims. (Cl. 51-219) This invention relates to a guide for use in sharpening the points of drill bits.

In sharpening the point of a drill bit the faces or heels of the end of the drill must be ground down so that the heels have the proper angular relationship. Heretofore, this has been accomplished by trial and error methods. The common practice has been to first grind the heels by estimation, then interrupt the grinding to measure the angles, and repeating this process until the proper angles have been obtained. This method requires a person to be skilled in the art of sharpening drill bits. Additionally, it is a time consuming and a tedious process, which adds to machine shop operating expenses.

The present invention is directed towards obviating the aforesaid difliculties by providing a guide which makes the process of sharpening drills a simple and efiicient task. In addition a sharpening job of superior quality is made possible.

Therefore, the principal object of this invention is to provide a visual guide having angular disposed faces, corresponding to the angular disposition of the heels of a properly formed bit, for aiding in grinding the heels of drill bits.

A further object is to provide in such a device a protective guard for preventing injury to ones fingers from the grinding stone.

A further object is to provide in such a device a holder for the work piece and access means for removing the work from the holder.

A further object is to generally improve the design and construction of guides for sharpening drill bits.

The means by which the foregoing and other objects of the present invention are accomplished and the manner of their accomplishment will be readily understood from the following specification upon reference to the accompanying drawings, in which:

Fig. 1 is a perspective view of the device.

Fig. 2 is a fragmentary view showing the device in use.

Fig. 3 is a top plan view of the device showing a drill in place.

Fig. 4 is an end elevational view of the device.

Referring now to the drawings in which the various parts are indicated by numerals, the device, which is preferably an integrally formed casting of metal, comprises a body portion 10, preferably having a size and shape adapted to be gripped by a person performing the grinding operation, as illustrated in Fig. 2. Thus one side of said body may be substantially straight as at 11 and the opposite side may be a curved surface as at 13 to fit the palm of the operators hand. Additionally, the butt end 14 of the body portion is preferably rounded to comfortably fit the hand.

A pair of adjoining skewed guide members 15, 17 are integrally formed at the forward end of body portion 10. The outwardface 19 of guide member is preferably disposed in a plane which is tilted forward at a given 2,821,820 Patented Feb. 4, 1958 angle with respect to a vertical plane through the bottom edge of face 19 and which is angled rearwardly at a fixed angle with respect to a vertical plane perpendicular to the longitudinal center line of the device. The outward face 21 of guide member 17 is preferably disposed in a plane which is tilted back with respect to a vertical plane through the bottom edge of face 21 at an angle equal to said given angle and which is angled rearwardly with respect to a vertical plane perpendicular to the longtiudinal center line of the device at an angle equal to said fixed angle. The line of intersection of the planes in which faces 19, 21 are respectively disposed preferably substantially intersects the longitudinal center line of a work piece, as a drill bit 23, positioned in the device. Thus, the faces 19, 21 of guide members 15, 17 are relatively disposed corresponding to the relative disposition of the faces or heels of a properly formed drill bit. Although a preferred disposition of the faces has been herein described, it should be understood that the invention is not limited to this precise disposition of the faces, but they may be formed at other desired relative positions, depending upon the desired shape of the drill point.

Guide members 15, 17 project above and depend below body portion 10, thereby providing guards 27 for the protection of the hands in the grinding process.

A longitudinal preferably V-shaped recess 29 is provided intermediate the sides 11, 13 of the body portion and extends throughout the length of the device, including the guide members 15, 17. The longitudinal center line of recess 29 is preferably coextensive with the longitudinal center line of the device. Guide members 15, 17 are provided with inner faces 31, 33, which respectively extend upwardly from the junctures of the sides of the V-shaped recess with the top of body portion 10, whereby the portion of said recess adjacent said guide members and the space between said inner faces provide an opening for the extension therethrough of the end of drill 23 positioned in recess 29.

A pair of diagonally disposed concave indentations 35 are provided in the top of body portion 10 adjacent the sides of recess 29 and in communication therewith. The indentations provide a means for gaining access to the drill 23 in removing it from the recess. Additionally, if desired, the operators thumb or thumbs may be positioned in the indentations for holding the drill securely in the recess during the grinding operation.

An aperture 37 is preferably provided in recess 29 adjacent the butt end 14, and may be used as a means for conveniently hanging the device on a hook or nail when not in use.

In using the device the drill 23 to be sharpened is placed in recess 29, as illustrated in Fig. 3. The end of the drill should be extended preferably slightly beyond the forward faces 19, 21 of the guide members and the drill held securely in place by either one or both hands of the operator, whichever is more convenient. If desired the thumbs may be brought to bear on the drill in the identations 35, as heretofore described. The sharpening operation may then be begun preferably by resting the bottom edge of one of the guide members against a support table 39 and bringing the end of the drill bit to bear against suitable grinding wheel 41, as illustrated in Fig. 2. First, one of the heels 43, 45 of drill 23 is ground, and then the other, the operator grinding until the heels 43, 45 are parallel to and an equal distance from forward faces 19, 21 respectively. This parallelism being easily determined by the operator who sights downwardly along the faces 19, 21 and visually compares the planes of the heels with the planes of the corresponding guide member faces.

It will be observed that preferably the drill should not be repositioned in the recess 29 when changing from the grinding of one heel to the other, but should be held in the samepositioh, relative to the device, during the sharpening process.

Thus, it will readily be understood a handy and eiii- I cient device is provided to aid in the sharpening of drill bits, and which provides a built-in means forguaging the slope of the heels of the drill during the grinding: operation, thereby obviating the time consuming necessity ofi'nterrupting the grinding process by taking :measurements of the angle of -.the slope.

I claim: 7

1. A guide for sharpening-drill bits comprising abody portion having sides anda rearward end shaped to comfortably-fit the grip of a persons hand, a pair. of adjoining guide members integrally formed at the forward e'nd of said body portion, each 'of'said guide members having a forward face, alongitudinal V.-'shaped seat'extendingthe length of said body portion and through said guide members, said seat being adapted to contain a'drill bit during the sharpening thereof, the forwardfaces of said guide members being disposed relative to one another and to said longitudinal V-shaped seat in a disposition corresponding to the disposition of the heels of a properly formed drill bit relative to one another and to the longitudinal center line of the drill bit, whereby a visual comparison aid is provided for guidingthe sharpening of drill bits, said guide members including upstanding portions and depending portions respectively projecting above and below said body portion whereby protection is provided against injury in sharpening said drill bits, a pair of indentations provided in said body portion communicating with said V-shaped seat-thereby furnishing the means for access to a drill seated in said V-shaped seat, and means provided in said body portion for hanging said device on a hook.

2. Aguide for sharpening drill bitscomprising a body portion, a pair of guide members integrally formed at the forward end of said body portion, each of said guide members having a forward face, a longitudinal V-shaped seat extending the length of said body portion and through said guide members, said seat being adapted to contain a drill bit during the sharpening thereof, the forward faces of said guide members being disposed relative to one another and to said longitudinal V-shaped seat in a disposition corresponding to' the disposition of the heels of a properly formed drill bit relative to one another and to the longitudinal center line of the drill bit, whereby a visual comparison aid is provided for guiding the sharpening of drill bits, said guide members including upstanding portions and depending portions respectively projecting above and below said body portion whereby protection is provided against injury in sharpening said drill bits, a pair of indentations provided in said body'po'rtion communicating with said V-shaped seat thereby furnishing the means for access to a drill seated in said V-shaped seat.

3. Aguide for sharpening drill bits comprising a body portion having sides and a rearward end shaped to comfortably fit the grip of a persons hand, a pair of adjoining guide members integrally formed at the forward end of said body portion, each of said guide members having a forward face, seat means provided'in said guide for holding a drill bit during the sharpening thereof, the forward faces of said guide members being disposed relative to one another and to said seat means in a disposition corresponding to the disposition of the heels of a properly formed drill bit relative to one another and to the longitudinal center line of the drill bit, whereby a visual comparison aid is provided for guiding the sharpening of drill bits, said guide members including upstanding portions and depending portions respectively projecting above and below said body portion whereby protection isprovided against injury in sharpening said drill bits, a pairiof indentations provided in said body portion communicating with said/seat means thereby furnishing the meansfor access toIa drill seated insaid seat means,.and means provided in said body portion for hanging said device on a ..hook.

4. A guide for sharpening drill bits comprising a body portion having sides and a rearward end shaped to comfortably fit the grip of a person's hand, a pair of adjoining guide members integrally formed at the forward end of said body portion, each of said guide members having a forward face, seat means provided in said guide for holding a drillbit during the sharpening thereof, the forward faces of said-guide members being disposed relative to one another and to said seat means in a disposition corresponding to the disposition of the heels of a properly formed drill bit relative to one another and to the longitudinal center line of the drill-bit, whereby a visual comparison aid is provided for guiding the sharpening of drill bits, 8. pair of indentations provided in said body portion communicating with said seat means thereby furnishing the means for access to a drill seated in said seat means, and means provided in said body portion for hanging said device on a book.

5. A guide for sharpening drill bits comprising a body portion having sides and a rearward end shaped to comfortably fit the grip of a persons hand, a pair of adjoining guide members integrally formed at the forward end of said body portion, each said guide member having a forward face, the forward faces of said guide members respectively being disposed in planes angularly intersect ing, one of said planes beingro'tated forwardly and the other of said planes being rotated rearwardly relative to said end, whereby a visual comparison aid is provided for guiding the sharpening of drill bits.

6. A guide for sharpening drill bits comprising a horizontal body portion, a pair ofadjoining guide members integrally formed atthe forward end of said body portion, one of said guide members having a forward face lying in a plane which is tilted forward at a givenangle relative to a vertical plane through the bottom edge of'said one of said guide members and which is angled rearwardly at a fixed angle relative to a vertical plane throughvthe longitudinal center line of said body portion, the other of said guide members having a forward face lying in aplane which is tilted back relative to a vertical plane through the bottom edge of said other of said guide members at an angle equal to said given angle and which is angled rearwardly relative to a vertical plane through the longitudinal center line of the body portion at an angle equal to said fixed angle, the relative disposition of the faces of said guide members thereby corresponding to the relative disposition of the heels of a properly formed drill bit, whereby a visual comparison aid is provided for use in sharpening drill bits, and means provided in said guide for seating said drill bits during said sharpening.

7. A guide for sharpening drill bits comprising a horizontal body portion, a pair of adjoining guide members integrally formed at the forward end of said body portion, one of said guide members having a forward face lying in a plane which is tilted forwardat a given angle relative to a vertical plane through the bottom edge of said one of said guide members and which is angled rearwardly at a fixed angle relative to a vertical plane through the longitudinal center line of said body portion, the other of said guide members having a forward face lying in a plane which is tilted back relative to a'vertical plane through the bottom edge of said other of said guide members at an angle equal to said given angle and which is angled rearwardly relative to'a vertical plane through the longitudinal center line of the body portion at an angle equal to said fixed angle, the relative disposition of the faces of said guide members thereby corresponding to the relative disposition of thelheels of a properly formed drill bit, whereby a visual comparison aidis' provided-for use in sharpening drill bits.

tReferences on following page 5 References Cited in the file of this patent 2,402,245 UNITED STATES PATENTS 2,471,443

288,069 Landers Nov. 6, 1883 1,576,311 Des Jardins Mar. 9, 1926 164,586 1,920,537 Ward Aug. 1, 1933 591,769

6 Freeland June 18, 1946 Munro May 31, 1949 FOREIGN PATENTS Germany Nov. 9, 1905 Great Britain Aug. 28, 1947 

